1. Field of the Invention
The present invention relates to a push-on switch that is operated by being pushed horizontally to a printed wiring board surface used for various electronic apparatuses.
2. Background Art
Recently, for operating an electronic apparatus, a method of performing a predetermined operation using an operating unit formed of arranged push-on switches has become widespread.
Various operation methods of push-on switches have been required with widespread use of various apparatuses. The demand for a push-on switch to be pushed horizontally to a printed wiring board surface increases. Small and light apparatuses are manufactured, so that especially surface-mounted-type push-on switches are preferred.
Japanese Patent Unexamined Publication No. H5-1126 discloses a conventional push-on switch that is operated by being pushed horizontally to a printed wiring board surface.
The conventional push-on switch is described with reference to FIG. 9 to FIG. 11.
The conventional push-on switch has center contact 2 and outside contacts 3 on the inner bottom surface of an upwardly opening recessed part of case 1. Case 1 is rectangular in a view from the upside. Center contact 2 is connected to terminals 4 projecting from the side faces of case 1, and outside contacts 3 are connected to terminals 5 projecting from the side faces of case 1.
Terminals 4 and terminals 5 are formed in a shape allowing mounting on a surface of so called a J bent type and are projected from the bottom of case 1 to the side.
Movable contact 6 is formed of a metal thin plate and has a dome shape projecting upwardly. The lower end of the outer periphery of movable contact 6 is placed on outside contacts 3 exposed in the recessed part of case 1 in an always contacting state.
At this time, the lower surface of the center top of movable contact 6 is faced to center contact 2 at a predetermined distance. Movable contact 6 is disposed so that the position thereof is regulated by the inner wall of the recessed part of case 1, and is adhered and held on intermediate step 1D of case 1 using flexible insulating sheet 7 having an adhesive layer on its lower surface. Here, flexible insulating sheet 7 has a structure for improving dust proofing performance of a contact part by adhering the center top of movable contact 6 to intermediate step 1D.
Operation body 8 made of insulating resin is a molded body including outer peripheral frame 9, pressing part 10 that is disposed in a central part of outer peripheral frame 9 and extends to the back side thereof in a bar shape, and operation part 11 projecting to the front side of outer peripheral frame 9.
As shown in FIG. 9 and FIG. 11, the front side corresponds to direction F of the arrow, and the back side corresponds to direction B of the arrow. Direction B corresponds to the pushing direction of operation part 11, and direction F corresponds to the returning direction thereof.
Operation body 8 is regulated by the wall of case 1, disposed movably only in the horizontal and longitudinal direction with respect to the bottom of case 1, and placed on flexible insulating sheet 7 so as to project operation part 11 to the front side (direction F).
Metallic cover 12 is disposed on case 1 so as to cover operation body 8 and is connected to case 1.
A central part of cover 12 has regulating part 13 that downwardly tilts toward the case 1 side, and the inner surface of regulating part 13 abuts on the tip of pressing part 10 of operation body 8.
The structure of the conventional push-on switch of the surface mounted type has been described.
Operations of the push-on switch are hereinafter described. FIG. 11 shows the OFF state of the switch. When operation part 11 of operation body 8 is pushed horizontally from the OFF state to the back side (direction B), operation body 8 moves in direction B.
At this time, the tip of pressing part 10 is guided to the downside of case 1 by regulating part 13 of cover 12, and the lower surface of pressing part 10 has a force of pressing down movable contact 6 via flexible insulating sheet 7.
When the force of pressing down movable contact 6 by pressing part 10 exceeds a predetermined value, movable contact 6 is inverted with click feeling. When inverted movable contact 6 contacts with center contact 2 on the lower surface of the center top, the ON state is obtained. Here, in the ON state, movable contact 6 electrically connects between center contact 2 and outside contacts 3, namely between terminals 4 and terminals 5.
When the operating force of operation body 8 to operation part 11 in direction B is removed, movable contact 6 returns to an original shape due to own elastic restoring force and pushes up pressing part 10 via flexible insulating sheet 7, operation body 8 returns to the forward original position with pressing part 10 guided by regulating part 13, and the switch returns to the OFF state as shown in FIG. 11.
In the conventional push-on switch of the surface mounted type that is pushed horizontally to the printed wiring board surface, terminals 4 and 5 are generally reflow-soldered to the printed wiring board of a used apparatus.
Since the operating direction is pushed horizontally to the mounted printed wiring board in the push-on switch of this type, the influence of the operating force on the connecting parts between terminals 4 and 5 and the printed wiring board must be considered, and the control of the mounted state to the printed wiring board is significant. The control is difficult to be simplified.